Improvement in winter vegetable oils



Patented Apr. 8, 1947 2,418,668 IMPROVEMENT DBKISNTER, VEGETABLE HarveyD. Royce, Savannah, Ga., assignor to The Southern Cotton Oil Company,Savannah, Ga., a corporation of New Jersey No Drawing. Application March1943, e

Serial No. 481,135

3 Claims. (01. 99-423) This invention relates to the treatment ofVegetable oils to inhibit the crystallization and deposition of stearintherefrom at low temperatures. The term stearin as used herein refers tothe precipitate that forms upon chilling such natural vegetable oils ascottonseed, peanut, olive, soybean, corn and the like, and embraces notonly tristearin, but also mixed glycerides'containing preponderantamounts of .palmitic, stearic, arachidic and other higher saturatedfatty acids, which comprise the bulk of the solid glycerides referred toin the trade as stearin. The stearin which separates from vegetable oilsupon chilling may also contain some of the more insoluble nonglyceridicconstituents of the oils, such as waxes,

sterols, higher alcohols and phosphatides.

More specifically, this invention relates to retarding the clouding anddeposition of stearin in salad oils. particularly winter cottonseed oil,and which may be defined more broadly as including any refined vegetableoil which does not deposit stearin on long standing at temperaturessubstantially above the range of temperatures hereinafter specified.During prolonged exposure to refrigeration or severe winter climatictemperatures in the range from 32 to 45 F., many salad oils lose theirclarity and brilliancy owing to separation of stearin, and while thisdoes not render the oils unfit for edible purposes, it detracts fromtheir appearance. Moreover, the stability of a mayonnaise or saladdressing emulsion is to a large extent dependent upon the resistance ofthe salad oil component to clouding and stearin separation. A well knownand standardized procedure used in the salad oil trade for evaluatingthe resistance of an oil to clouding, commonly referred toas' the coldtest, consists in aging a carefully dried sample of the oil in a bath ofcrushed ice and water at 32 F. and noting the elapsed time until a cloudor deposit of stearin is visible. The eifectiveness of any inhibitor isdetermined by a comparison of such elapsed time when chilling thetreated oil with the elapsed time when chilling the untreated oil. Asecondary factor in determining the eifectiveness of the inhibitor isthe amount of clouding or deposit when the cooling period is furtherprolon ed. V

The present invention comprises a vegetable oil of the character abovespecified to which has been added. so as to be colloidally dispersedtherein, a, small percentage of aluminum tristearate and which hastheproperty of withstanding a severe cold test varying from a minimum of24 hours to a maximum in excess of 40 hours. The specified additive maybe appropriately designated a. "cloud inhibitor. inasmuch as its primaryobiect and efiect is to retard the clouding of the oil at lowtemperature. The effective concentration range of the cloud inhibitor israther narrow. par- 2 r ticularly when expressed in terms of metalconcentration. In general the most effective range is from 1 to 30 partsof metal per 1,000,000 parts of oil. The effective concentration rangeof the cloud inhibitor whenexpressed interms of the aluminum soap maybe'from 0.002 to 0.2 per cent. of the oil. Larger percentages than thosespecified may be used but without substantial improvement as a cloudinhibitor.

The soaps used in the present invention may be prepared conveniently bydouble decomposition, induced by mixing aqueous solutions of'the solublemetal salts with aqueous alkali soap solutions, or by heating the metalacetates with fatty acids. However, the invention is not limited by themethod of preparation of the cloud inhibitor, and the soaps may beformed in situ in the salad oils by heating them with reactive aluminumcompounds.

The following is an example of the application of the invention towinterized cottonseed oil:

In a winterized cottonseed oil having a cold test of '7 hours 0.01 percent. by weight of aluminum tristearate was dissolved by heating andstirring. The product withstood a cold test of 40 hours.

What I claim and desire to protect by Letters Patent is:

1. A winter vegetable oil, characterized, by substantial stabilityagainst resistance to clouding and stearin separation, havingcolloidally dispersed therein a small percentage of aluminum tn'stearateadequate to enable the oil to withstand a cold test of at least 24hours.

' 2. A winter vegetable oil, characterized. by substantial stabilityagainst resistance to cloudin and stearin separation, having colloidallydispersed therein aluminum tristearate the concentration range of which,expressed in terms by weight of the soap, is over .005per cent.

3. A winter vegetable oil, characterized by substantial stabilityagainst resistance to clouding and stearin separation, havingcolloidally dispersed therein suificient aluminum tristearate, not less,in terms by weight of the soap, than about .01 per cent, effective toenable the oil to withstand a cold test of at least 40 hours. I

HARVEY D. ROYCE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Name Date Black May 25, 1943 OTHER REFERENCES INumber

